Field of the Invention
The present invention relates to racket frames used in tennis. In more detail, the present invention relates to racket frames having a function for adjusting weight balance.
Description of the Related Art
Weight balance of a racket frame greatly affects characteristics of a tennis racket such as inertia moment etc. The weight balance affects basic performances such as flight, ease of swinging, and sensation of hitting etc. The weight balance is often changed in accordance with aptitude and preference of a player. Changing of the weight balance is performed by attaching a weight to the racket frame for adjustment.
For example, a weight is affixed to a racket frame. In order to additionally change the weight balance in the racket frame having the weight affixed thereto, it is necessary to replace the weight etc. Thus, time and effort are needed for adjusting the weight balance of the racket.
JP No. 3746268 discloses a dynamic damper in which vertical frame parts and horizontal frame parts are integrally molded into a grid pattern. The dynamic damper is affixed to a frame. In the dynamic damper, a string is threaded through openings formed on the grid pattern. In order to replace the dynamic damper, it is necessary to restring the string.
JP No. 4363006 discloses a dynamic damper detachably attached to a desired position on a racket frame. In the dynamic damper, a belt is attached to the frame. In this attachment structure, the belt enables the dynamic damper to be detachable. This dynamic damper can be replaced without restringing the string.
It is conceivable to attach a weight using the attachment structure of JP No. 4363006. With this attachment structure, replacing or reaffixing the weight can be performed easily compared to a structure of affixing the weight. By adopting this attachment structure, the weight balance can be adjusted easily.
In the attachment structure, the belt is also wound on an outer circumferential surface of the racket frame. The belt may make contact with the ground or a structure. With such contact, the position of the weight may shift or the weight may become separated from the racket frame. Such attachment structure may change the weight balance of the racket frame.
An objective of the present invention is to provide a racket frame that enables adjusting of weight balance easily with certainty.